The survey also finds that state Assemblyman Tim Donnelly has about 15 percent support among likely voters in the June 3 primary, while former U.S. Treasury official Neel Kashkari has about 10 percent.

The poll has a margin of error of plus or minus 4.9 percentage points, making the race for second a statistical dead-heat.

While Brown remains the heavy favorite in the race, the poll also shows his approval rating, once at an all-time high of 60 percent in January, down to 54 percent among likely voters.